Japan suffering from worst flu season in 10 years

Face masks are being seen everywhere in Japan at the peak of flu season, as the number of patients is increasing at the fastest pace in 10 years.

The number of patients who sought treatment at medical institutions subject to a survey stood at 42.62 on average in the latest week from Jan. 30 to Feb. 5. That was the highest at this time of the year since 2002.

The total number of flu patients in Japan is estimated to be about 2.11 million.

Starting this month, the number of patients who have contracted different types of flu strains is also increasing.

This influenza season features the spread of a Type A Hong Kong flu for the first time in five seasons. About 90 percent of patients were contracting that type of virus until January. From this month, however, patients that are suffering from a Type B influenza are also increasing in some areas.

“Antibodies that were gained as a result of infection are maintained for certain periods. As time passes, however, their effects wane. As a Type A Hong Kong flu is spreading after a long interval, people may have lost their immunities,” said Hideki Hasegawa, director of the Department of Pathology at National Institute of Infectious Diseases (NIID).

Because of the various types of strains, there is a growing fear that the current flu season will be a long-lasting one.

In the Tokyo metropolitan area, until mid-January, the number of patients was relatively small. In recent weeks, however, it has increased sharply there. In addition, the number of patients has been hovering at high levels in the Tokai and Shikoku regions since early January.

According to an announcement from the NIID, the number of patients per medical institution stood at 35.95 on a national average in the previous week from Jan. 23-29.

In the latest week, however, the figure jumped to 50.94 in Saitama Prefecture, 50.84 in Chiba Prefecture, 45.20 in Tokyo and 48.86 in Kanagawa Prefecture.

In the Kinki region, the corresponding figures were hovering around 40 in the latest week, almost the same as that in the previous week. For example, it stood at 44.81 in Osaka Prefecture and 42.46 in Hyogo Prefecture.

In the previous week, prefectures with the largest numbers of patients per medical institution were Fukui, Kochi and Aichi. In all of the three prefectures, their figures dropped to 64.41, 54.21 and 47.38 respectively in the latest week. However, the figures were still at high levels.

In Chugoku and Kyushu regions, high levels also continued in the latest week with the number of patients at 51.64 in Yamaguchi Prefecture, 55.36 in Miyazaki Prefecture and 45.67 in Oita Prefecture.

The number of flu patients is also increasing in areas affected by the Great East Japan Earthquake. In Iwate Prefecture, the number increased from 45.52 in the previous week to 58.98 in the latest week, the second highest in Japan following Fukui Prefecture.

The H7N9 strain of the avian influenza virus that surfaced in China earlier this year could cause a pandemic in Japan due to a lack of immunity in all age groups, according to an international team of scientists.

A team of researchers has developed a system that can detect whether subjects carry infectious diseases, such as a new strain of influenza, even when they do not have a fever, which is usually a telltale sign at quarantine inspection points.